diff --git a/include/osg/ref_ptr b/include/osg/ref_ptr
index 86bb83fac..948d2f0bb 100644
--- a/include/osg/ref_ptr
+++ b/include/osg/ref_ptr
@@ -18,6 +18,8 @@
 
 namespace osg {
 
+template<typename T> class observer_ptr;
+
 /** Smart pointer for handling referenced counted objects.*/
 template<class T>
 class ref_ptr
@@ -29,7 +31,7 @@ class ref_ptr
         ref_ptr(T* ptr) : _ptr(ptr) { if (_ptr) _ptr->ref(); }
         ref_ptr(const ref_ptr& rp) : _ptr(rp._ptr) { if (_ptr) _ptr->ref(); }
         template<class Other> ref_ptr(const ref_ptr<Other>& rp) : _ptr(rp._ptr) { if (_ptr) _ptr->ref(); }
-
+        ref_ptr(observer_ptr<T>& optr) : _ptr(0) { optr.lock(*this); }
         ~ref_ptr() { if (_ptr) _ptr->unref();  _ptr = 0; }
 
         ref_ptr& operator = (const ref_ptr& rp)
diff --git a/src/osgDB/DatabasePager.cpp b/src/osgDB/DatabasePager.cpp
index 31d77d6ab..36fdfba26 100644
--- a/src/osgDB/DatabasePager.cpp
+++ b/src/osgDB/DatabasePager.cpp
@@ -1612,8 +1612,8 @@ void DatabasePager::removeExpiredSubgraphs(const osg::FrameStamp& frameStamp)
         itr != _activePagedLODList.end();
         )
     {
-        osg::ref_ptr<osg::PagedLOD> plod;
-        if (itr->lock(plod))
+        osg::ref_ptr<osg::PagedLOD> plod(*itr);
+        if (plod.valid())
         {
             int delta = frameStamp.getFrameNumber() - plod->getFrameNumberOfLastTraversal();
             if (delta>1)
@@ -1643,8 +1643,8 @@ void DatabasePager::removeExpiredSubgraphs(const osg::FrameStamp& frameStamp)
         itr != _inactivePagedLODList.end();
         )
     {
-        osg::ref_ptr<osg::PagedLOD> plod;
-        if (itr->lock(plod))
+        osg::ref_ptr<osg::PagedLOD> plod(*itr);
+        if (plod.valid())
         {
             int delta = frameStamp.getFrameNumber() - plod->getFrameNumberOfLastTraversal();
             if (delta>1)
@@ -1702,8 +1702,8 @@ void DatabasePager::removeExpiredSubgraphs(const osg::FrameStamp& frameStamp)
         itr!=_inactivePagedLODList.end() && countPagedLODsVisitor._numPagedLODs<numToPrune;
         )
     {
-        osg::ref_ptr<osg::PagedLOD> plod;
-        if (itr->lock(plod) && countPagedLODsVisitor._pagedLODs.count(plod.get())==0)
+        osg::ref_ptr<osg::PagedLOD> plod(*itr);
+        if (plod.valid() && countPagedLODsVisitor._pagedLODs.count(plod.get())==0)
         {
             countPagedLODsVisitor.removeExpiredChildrenAndCountPagedLODs(plod.get(), expiryTime, expiryFrame, childrenRemoved);
 
@@ -1721,8 +1721,8 @@ void DatabasePager::removeExpiredSubgraphs(const osg::FrameStamp& frameStamp)
         itr!=_activePagedLODList.end() && countPagedLODsVisitor._numPagedLODs<numToPrune;
         )
     {
-        osg::ref_ptr<osg::PagedLOD> plod;
-        if (itr->lock(plod) && countPagedLODsVisitor._pagedLODs.count(plod.get())==0)
+        osg::ref_ptr<osg::PagedLOD> plod(*itr);
+        if (plod.valid() && countPagedLODsVisitor._pagedLODs.count(plod.get())==0)
         {
             countPagedLODsVisitor.removeExpiredChildrenAndCountPagedLODs(plod.get(), expiryTime, expiryFrame, childrenRemoved);